1. Field of the Invention
The present invention relates generally to gas turbine engine combustors and, more specifically, to a combustor dome assembly.
2. Description of Related Art
A conventional gas turbine engine combustor includes radially spaced outer and inner combustor liners joined at an upstream end thereof by a combustor dome. The combustor dome is typically made of sheet metal and is part of a combustor dome assembly that includes a plurality of circumferentially spaced carburetors therein, with each carburetor including a fuel injector for providing fuel and an air swirler for providing swirled air for mixing with the fuel for creating a fuel/air mixture discharged into the combustor between the two liners. The mixture is burned for generating combustion gases which flow downstream or aftwardly through the combustor to a turbine nozzle suitably joined to the aft end of the combustor. Immediately downstream of the turbine nozzle is a high-pressure turbine which extracts energy from the combustion gases for powering a compressor disposed upstream of the combustor which provides compressed air to the engine.
A significant consideration in the design of the gas turbine engine combustor is serviceability of the life-limiting parts therein. For example, a typical dome assembly includes a baffle extending from the air swirler and spaced from the combustor dome for providing a channel therebetween for channeling compressor air for cooling at least the baffle itself. The baffle is subject to intense heating from combustion and, thus, is one life-limiting part which is replaced at periodic intervals.
The baffle is typically welded and/or brazed to the dome and, typically, requires replacement of the entire dome assembly therewith or substantial disassembly work at the periodic service intervals. Such baffle replacement. service is relatively expensive and requires a significant amount of time. U.S. Pat. No. 5,117,637 entitled "Combustor Dome Assembly" discloses a gas turbine engine combustor dome assembly mounting ring fixedly joined to the dome around a dome eyelet in a combustor dome. A baffle and a carburetor are fixedly joined to the mounting ring. The carburetor is joined to the mounting ring by its air swirler. The mounting ring is designed for assembly with reduced stackup clearances and easy disassembly for servicing. Each mounting ring is fixedly joined to a respective dome eyelet by welding or brazing. U.S. Pat. No. 5,117,637 is incorporated herein by reference.
The mounting ring also provides sealing and air leakage control between the air swirler of the carburetor and dome which results in good combustor performance and a good Pattern Factor. Leakage control is expensive to provide. Other designs have a lower cost dome assembly which has more leakage and produces a higher less desirable Pattern Factor. It is highly desirable to provide a low cost dome assembly which has been demonstrated to provide good leakage control. It is also desirable to provide a low cost dome assembly which eliminates brazed joints.